So with the fantastic Dovetail Direct over, there was the "route hopping" that caught me quite off guard. In simple terms: it appears routes can now be interlinked! This creates so many new possibilities because now we can link routes, creating longer and more complete services. About time East Coastway together with BML gets this treatment. There is a small branch between Wivelsfield and Lewes with only two stations between it: Plumpton and Cooksbridge. Having a fairly minor extension like this will allow Newhaven freight trains to be able to run as far as Clapham, and Ore trains to Victoria and Eastbourne without the annoyance of unloading and reloading different routes.
While the connection between the East Coastway and London Commuter would be amazing, route-hopping does not allow for what you have just described. It only works on foot by using a loading screen to load another route.